Electrical current can be measured by connecting a current meter in series with the wire. In many cases, however, disconnecting the wire to connect the current meter can be inconvenient. For example, the wire can be tightly grouped in a bundle with several other wires making it difficult to individually disconnect the wire of interest. Another example of the inconvenience is where a terminal to which the wire is connected is not conveniently located or is inaccessible, requiring the wire to be cut for the current meter to be connected in series. It is time consuming to reconnect the two ends of the cut wire after a measurement is taken, and can be dangerous in situations where relatively high current is carried by the wire. Additionally, the integrity of the wire is compromised by cutting and reconnecting, thus, potentially raising reliability problems.
A clamp probe connected to a conventional multimeter can be used to measure electrical current without the need for disconnecting a wire. The clamp probe is opened, the wire is inserted into the clamp, and the clamp is closed to take a current measurement. The closed clamp includes a core of ferromagnetic material, which when closed, represents the core of a transformer. The wire passing through the clamp represents the primary winding. As known, a current flowing in the wire induces a magnetic flux in the core of the transformer, which in turn, induces a current in a secondary winding of the transformer. Using these physical phenomena, the magnitude and polarity of the current in the clamped wire can be determined based on the current induced in the secondary winding and the characteristics of the transformer formed by the clamped wire.
A known clamp meter is designed with the clamp integrated into the body of the meter, which can provide the convenience of taking a measurement using one hand. That is, only one hand is used to open and close the clamp for clamping a wire and to take a current reading. “One-handed” clamp meters are generally acceptable for applications where the display can be easily viewed by the technician with the meter clamped to the wire for measurement. However, problems with reading the measurement can arise where the wire is difficult to reach or cannot be readily singled-out from amongst adjacent wires.
FIG. 6 illustrates an exploded view of a known jaw assembly. The known jaw assembly includes housings that are split in two approximately equal pieces. In particular, neither housing piece of the known jaw assembly has a volume approximately sufficient to individually contain a current sensing core. Additionally, the known jaw assembly includes separate end caps that are not integrally formed with either piece of the housing. It is therefore more difficult to use the known jaw assembly to select an individual wire from a group of wires because the cross-section of the known jaw assembly is enlarged due to the location of the joints between the housing pieces and the separate end caps.